Legionnaires' disease
noun
Le·gion·naires' disease
ˌlē-jə-ˈnerz- 
variants
or less commonly Legionnaire's disease
: pneumonia that is caused by a bacterium (Legionella pneumophila), is characterized initially by symptoms resembling influenza (as malaise, headache, and muscular aches) followed by high fever, cough, diarrhea, severe pneumonia, and mental confusion, and that may be fatal especially in elderly and immunocompromised individuals
Examples of Legionnaires' disease in a Sentence
Recent Examples on the Web
The letter from the department did not list the name of the gym, but WFTV reported that a Crunch Fitness in Ocoee -- 12 miles west of Orlando -- had members reporting cases of Legionnaires' disease.
—
Mary Kekatos, ABC News, 5 Dec. 2025
According to the Oakland County Health Department, a custodial employee within the sheriff's administration building tested positive for Legionnaires' disease.
—Alysia Burgio, CBS News, 5 Dec. 2025
The fatality rate among people with Legionnaires' disease is about 10%, according to the CDC.
—Christina Hall, Freep.com, 5 Dec. 2025
Cooling towers are often a source of Legionnaires' disease outbreaks because they’re filled with water.
—Cara Lynn Shultz, PEOPLE, 10 Sep. 2025
This 1978 electron microscope image made available by the Centers for Disease Control and Prevention shows Legionella pneumophila bacteria which are responsible for causing the pneumonic disease Legionnaires' disease.
—Kate Plummer, MSNBC Newsweek, 29 Aug. 2025
Considered a rare disease, the American Lung Association said Legionnaires' disease is a growing health concern.
—Thao Nguyen, USA Today, 27 Aug. 2025
Health officials in New York City are investigating a Bronx apartment complex after two residents tested positive for Legionnaires' disease.
—Rebecca Cohen, NBC news, 26 Aug. 2025
Cooling towers, water systems typically located atop buildings, can emit mist containing Legionella bacteria, which causes Legionnaires' disease.
—Diana Leyva, Nashville Tennessean, 5 Aug. 2025
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Mary Kekatos, ABC News, 5 Dec. 2025
According to the Oakland County Health Department, a custodial employee within the sheriff's administration building tested positive for Legionnaires' disease.
—Alysia Burgio, CBS News, 5 Dec. 2025
The fatality rate among people with Legionnaires' disease is about 10%, according to the CDC.
—Christina Hall, Freep.com, 5 Dec. 2025
Cooling towers are often a source of Legionnaires' disease outbreaks because they’re filled with water.
—Cara Lynn Shultz, PEOPLE, 10 Sep. 2025
This 1978 electron microscope image made available by the Centers for Disease Control and Prevention shows Legionella pneumophila bacteria which are responsible for causing the pneumonic disease Legionnaires' disease.
—Kate Plummer, MSNBC Newsweek, 29 Aug. 2025
Considered a rare disease, the American Lung Association said Legionnaires' disease is a growing health concern.
—Thao Nguyen, USA Today, 27 Aug. 2025
Health officials in New York City are investigating a Bronx apartment complex after two residents tested positive for Legionnaires' disease.
—Rebecca Cohen, NBC news, 26 Aug. 2025
Cooling towers, water systems typically located atop buildings, can emit mist containing Legionella bacteria, which causes Legionnaires' disease.
—Diana Leyva, Nashville Tennessean, 5 Aug. 2025
Cite this Entry
“Legionnaires' disease.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Legionnaires%27%20disease. Accessed 22 Dec. 2025.
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